1. Field of the Invention
The present invention relates to an automatic door lock releasing apparatus that is automatically started to release a door lock during a collision accident involving a moving object such as a vehicle so that a passenger locked up in the inside is immediately rescued.
2. Description of Related Art
For example, as a conventional automatic door lock releasing apparatus used in a moving object such as a vehicle, there is a door lock releasing apparatus in which an electromechanical sensor, which closes a contact by detecting a collision acceleration during a collision of the vehicle, is used to determine release of a door lock of the vehicle.
In addition, there is a conventional door lock releasing apparatus that determines release of a door lock in such a manner that when the level of an acceleration signal obtained from an electronic acceleration sensor (hereinafter abbreviated as a G sensor) installed in a vehicle exceeds a specified value, the door lock is released.
Furthermore, conventionally, G sensors used exclusively for a passenger protection system that operates a front collision air bag, a side collision air bag, and the like are also installed in a vehicle, in addition to the above-mentioned G sensor that determines release of a door lock. Therefore, a plurality of G sensors exist in a vehicle.
Now, in some cases, a large acceleration occurs at times other than during vehicle collisions for example travel on rough surfaces. Thus, a conventional door lock releasing apparatus has a problem in that when release of a door lock is to be determined by an electromechanical sensor, it is difficult to distinguish between an acceleration occurring during travel on rough surfaces and an acceleration occurring during a collision.
Conventionally, there has also been a problem even in a case where release of a door lock is to be determined on the basis of the level of an acceleration signal obtained from a G sensor, in that if the G sensor is set so as not to function erroneously when a large acceleration occurs at a time of other than a collision, its proper operation for determining release of a door lock is not ensured at a time of a low speed collision.
The present invention has been made in order to solve the problems as mentioned above. An object of the present invention is to provide an automatic door lock releasing apparatus that determines release of a door lock by distinguishing between non-collision such as travel on rough surfaces and a hard hit on the bottom of a vehicle and an actual vehicle collision in a vehicle accident or the like and thus correctly determining occurrence of a vehicle collision.
An automatic door lock releasing apparatus according to the present invention comprises a plurality of acceleration sensors for detecting acceleration in a plurality of directions; a plurality of decelerating direction integrating means each provided in correspondence with one of the plurality of acceleration sensors for integrating a deceleration signal of an accelerating direction within a specified sampling time, the acceleration signal being included in each of acceleration signals of the plurality of directions obtained from the plurality of acceleration sensors; a plurality of accelerating direction integrating means each provided in correspondence with one of the plurality of acceleration sensors for integrating a signal of an accelerating direction within a specified sampling time, the signal being included in each of acceleration signals of the plurality of directions obtained from the plurality of acceleration sensors; a plurality of first coefficient means each provided in correspondence with one of the plurality of acceleration sensors for weighting an output of the accelerating direction integrating means by multiplying it by a specified coefficient; a plurality of subtracting means each provided in correspondence with one of the plurality of acceleration sensors for determining a velocity signal by subtracting the integral value outputted from the first coefficient means from the integral value outputted from the decelerating direction integrating means; an arithmetic processing means for receiving a plurality of velocity signals outputted from the plurality of subtracting means and then determining a resultant velocity of the plurality of velocity signals; and a signal generating means for comparing the resultant velocity outputted from the arithmetic processing means with a specified threshold value and then generating and outputting a start signal when the resultant velocity exceeds the specified threshold value.
In addition, in an automatic door lock releasing apparatus according to the present invention, the decelerating direction integrating means includes a positive side acceleration detecting means for detecting a positive side acceleration included in the acceleration signals obtained from the plurality of acceleration sensors; and an integration processing unit for integrating an input of the positive side acceleration outputted from the positive side acceleration detecting means and thereby calculating an integral value of the positive side acceleration.
In addition, in an automatic door lock releasing apparatus according to the present invention, the accelerating direction integrating means includes a negative side acceleration detecting means for detecting a negative side acceleration included in the acceleration signals obtained from the plurality of acceleration sensors; and an integration processing unit for integrating an input of the negative side acceleration outputted from the negative side acceleration detecting means and thereby calculating an integral value of the negative side acceleration.
Moreover, in an automatic door lock releasing apparatus according to the present invention, the arithmetic processing means includes a plurality of square processing units each provided in correspondence with one of the plurality of subtracting means for squaring a velocity signal outputted from each of the plurality of subtracting means; a second coefficient means for weighting an output from part of the plurality of square processing units by multiplying it by a specified value; an addition processing unit for adding outputs of the plurality of square processing units and the second coefficient means; and a square root processing unit for determining a square root value of an output of the addition processing unit.
Moreover, in an automatic door lock releasing apparatus according to the present invention, the signal generating means includes a comparator for comparing the resultant velocity outputted from the arithmetic processing unit with a specified threshold value; and a one-shot timer for generating and outputting the start signal according to an output from the comparator.
Furthermore, in an automatic door lock releasing apparatus according to the present invention, part of the plurality of acceleration sensors are acceleration sensors for a passenger protection apparatus; and the automatic door lock releasing apparatus further includes a collision determining means for receiving an input of an acceleration signal outputted from an acceleration sensor for the passenger protection apparatus and outputting a start signal when the acceleration signal exceeds a specified value.
Furthermore, an automatic door lock releasing apparatus according to the present invention further includes a logical sum means for calculating a logical sum of the start signal from the signal generating means and the start signal from the collision determining means.